BMW Intelligent Battery Sensor (IBS)

HUB: BMW
Updated Monday Feb 12, 2018

1. What is BMW Intelligent Battery Sensor

BMW cars depend greatly on the battery not just for starting the engine but also for many other functions. Because the battery is so crucial on a BMW, the Intelligent Battery Sensor (IBS) is used to monitor various battery parameters such as voltage, current, and temperature.

The IBS sensor on a BMW is mounted on the negative battery terminal. The IBS sensor is mounted on top of battery negative pole has the ground cable and two connectors. One of the IBS cables connect gets power from the positive terminal. The second cable is indirectly connected to the DME and measures the battery load. This is known as the Bit Serial Data Interface or BSD.

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2. Purpose of BMW IBS

BMW IBS sensor measures several battery parameters such as:

Terminal Voltage
Charging current
Discharge current
Battery Temperature
SoC (State of Charge)
SoH (State of Health

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3. Symptoms of a bad IBS sensor on a BMW

BMW battery will drain when parked
BMW will not go to "sleep", drains battery
Dead car battery
IBS not able to wake up the DME
Voltage fault, DME not on. This can be caused due to a short to B+ line.
Voltage fault DME on, which can be caused to a ground short

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4. How to troubleshoot IBS sensor

Fault codes related to the IBS sensor are stored in the DME module. The DME will perform a check of the current, voltage, temperature. To find out if the IBS sensor on BMW is defective we scan the DME module for fault codes. You will need a BMW specific scanner for this task. Follow this guide on how to scan BMW codes.